Washing, cleaning and care for the body are a basic human need and modern industry continuously attempts to meet these human needs in a variety of ways. Long-lasting elimination or at least reduction of the body odor and underarm wetness are especially important for daily hygiene.
Body odor is caused by the bacterial decomposition of the constituents of the initially odorless sweat. The decomposition products, which contribute significantly to the body odor, in particular to the axillary body odor, can be divided into three classes: short-chain C4-C10 fatty acids, which may be linear, branched, saturated and unsaturated (for example, isovaleric acid, 3M2H) constitute the first class, short-chain linear or branched sulfanyl alcohols constitute the second class, the third class includes various steroid hormones and their metabolic products (for example, 5-alpha androstenol and 5-α androstenone).
Body odor can therefore be combated by preventing the bacterial decomposition of the sweat. State-of-the-art antimicrobial substances are used to prevent the bacterial decomposition of the sweat. These reduce the number of sweat-decomposing bacteria on the skin by killing them and/or inhibiting the growth of these bacteria. Active substances are also known that reduce and/or prevent the formation of decomposition products by blocking bacterial enzymes. It is furthermore a commonly known fact that volatile decomposition products are absorbed by physical and/or chemical interaction, which avoids unpleasant body odor.
Moreover, body odor can be combated by preventing the perspiration of the body. Cosmetic antiperspirants from the prior art contain at least one antiperspirant salt. To achieve a high degree of sweat reduction, aluminum zirconium halides are preferably used in the prior art. The antiperspirant effect of these salts can be further improved by thermal treatment and the addition of ligands or phosphates, for example.
The transparent appearance of cosmetic agents is frequently desired by consumers. Cosmetic agents in the form of transparent emulsions are known. For transparent emulsions, the droplets distributed in the dispersed phase should have as small a mean particle diameter as possible, generally significantly below about 1000 nm, preferably below about 400 nm or even below about 200 nm.
Such agents of the prior art can generally lead to an impaired skin tolerance due to the high emulsifier content required to stabilize the emulsion. Furthermore, when such agents of the prior art are applied textile stains can form, which are perceived as undesirable by the consumer.
Cosmetic agents in the form of microemulsions that have a comparatively lower emulsifier content have therefore also already been developed. For example, WO96/28132 A2 discloses microemulsion gels as the basis for deodorizing or antiperspirant preparations, containing at least one polyethoxylated and/or polypropoxylated O/W emulsifier. WO00/61083 A1 discloses transparent microemulsions with about 2 or more non-ionic surfactants, of which one has an HLB value greater than about 10 and the other has an HLB value less than about 10.
Among other things, EP 820758 A2 deals with the stability of microemulsions and provides stable microemulsions, which contain a polyethoxylated and/or polypropoxylated O/W emulsifier, an oil component and a cationic surfactant, wherein the total quantity of emulsifier is about 2 wt. % or less.
However, the stability of microemulsions is often still in need of improvement, in particular when they are exposed to large temperature fluctuations, meaning that initially clear emulsions become cloudy over time. Even the addition of perfume oils cannot always guarantee the maintenance of a good level of transparency.
The present disclosure therefore addressed the problem of preparing cosmetic agents in the form of transparent microemulsions, in particular for deodorizing and/or antiperspirant preparations, which have a high storage stability under fluctuating temperatures. In the process, a good skin tolerance and a low residue formation, in particular on textiles, should preferably be ensured. Furthermore, these agents should also have an excellent antiperspirant and/or deodorizing effect.
Surprisingly, this problem was solved by the fact that, besides an oil component and an antiperspirant and/or deodorizing active ingredient, the cosmetic agent contains a combination of specific O/W emulsifiers in a specific weight ratio. Due to a low emulsifier concentration, a good skin tolerance can also be achieved.